JPH11145492A - Apparatus and method of forming photosensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a large no. of photosensors, having a high quality and good uniformity by introducing a material gas between adjacent partition- like electrodes, and flowing it perpendicularly to the substrate carrying the direction to enhance a photoelectric conversion efficiency over a wide area. SOLUTION: During glow-discharging, cathode electrodes 1002 are kept, e.g., at a positive potential (self bias) of +30 V or more relative to a grounded anode electrode including a strip-like member 1000. Partition-like electrodes 1003 forming fin-like parts of the cathode electrodes are disposed perpendicular to the strip-like member 1000 carrying direction. To precisely control the compsn. in the film thickness direction for depositing a film on the conductive strip-like member 1000, a material gas is fed into discharge spaces between the adjacent partition-like electrodes 1003 and flowed perpendicularly to the strip-like member 1000 moving direction, i.e., along the width of the member 1000 between the electrodes 1003.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus and a method for forming a photovoltaic element. More specifically, by forming the i-type semiconductor layer by controlling the composition ratio in the film thickness direction,
The present invention relates to an apparatus and a method capable of forming a photovoltaic element having high photoelectric conversion efficiency and high quality and excellent uniformity over a large area. In particular, it is suitably used as a roll-to-roll type photovoltaic device forming apparatus and method for mass-producing photovoltaic devices such as solar cells using amorphous silicon or amorphous silicon alloy.

[0002]

2. Description of the Related Art Photovoltaic elements, which are photoelectric conversion elements for converting sunlight into electric energy, have been widely applied as small power sources for consumer use such as calculators and wristwatches. Has attracted attention as a technology that can be put to practical use as a so-called fossil fuel alternative electric power. A photovoltaic element is a technique using photovoltaic power generated at a pn junction of a semiconductor. A semiconductor such as silicon absorbs sunlight to generate photocarriers of electrons and holes, and the photocarriers are converted to a pn junction. And drifts out due to the internal electric field.

[0003] As a material constituting a semiconductor of such a photovoltaic element, for example, single crystal silicon, polycrystalline silicon, and amorphous silicon can be cited.

It is desirable to use single crystal silicon from the point of efficiency of converting light energy into electromotive force. However, since crystalline silicon such as single crystal has an indirect optical edge, light absorption is small, and Crystalline silicon solar cells require a thickness of at least 50 μm to absorb incident light.
In addition, the band gap of single crystal silicon is about 1.1 eV, which is narrower than 1.5 eV which is suitable for a solar cell.

On the other hand, when polycrystalline silicon is used in place of single crystal silicon, production costs can be reduced. However, the problem of the indirect optical edge cannot be solved,
The thickness of solar cells cannot be reduced. Further, polycrystalline silicon has grain boundaries and other problems, and there are many problems to be solved.

[0006] On the other hand, amorphous silicon formed by chemical vapor deposition (CVD) has been regarded as promising in terms of increasing the area and reducing the cost. However, although this amorphous silicon solar cell has been widely used as a small power source for consumer use, there is still a problem in terms of high efficiency and stability as a power element.

As a method for solving such a problem of the amorphous silicon, there are the following reports.

US Pat. No. 2,949,498 describes using multiple batteries to improve the efficiency of photovoltaic cells. Although a pn junction crystal semiconductor was used in this multi-cell, the idea is that both amorphous and crystalline are common, and the solar spectrum is efficiently absorbed by photovoltaic elements with different band gaps. ,
The power generation efficiency is improved by increasing Voc.

As an improved version of the above-mentioned multiple battery, US Pat. No. 4,377,723 discloses that three elements are stacked using amorphous silicon having a pin junction and amorphous silicon germanium as a photovoltaic element. So-called a-SiH / a-SiGe: H / a that increases Voc of the entire device
-A triple-cell solar cell of -SiGe: H has been reported. In this solar cell, since amorphous silicon germanium is used for the second photovoltaic element layer, the thickness of the i-layer of the second photovoltaic element can be reduced, and the generation of photogenerated carriers can be reduced. The characteristics of the solar cell are improved by the payment effect.

However, the following problems have been pointed out when amorphous silicon germanium is used as a material constituting a semiconductor of a photovoltaic element.

First, germanium acts as an impurity that lowers the characteristics of amorphous silicon, and the photovoltaic characteristics of a solar cell made of silicon, germanium, and hydrogen deteriorate.

Second, in order to improve the photovoltaic characteristics of the above-mentioned amorphous silicon germanium alloy (hereinafter abbreviated as amorphous SiGe alloy), amorphous SiG
It is necessary to not only compensate for the defect state caused by the introduction of germanium into the e-alloy, but also to significantly improve the electronic state in the energy gap.

As a countermeasure against this, Japanese Patent Publication No. Sho 63-48197
In order to produce a high-quality amorphous SiGe alloy, Japanese Unexamined Patent Publication (Kokai) No.
Amorphous SiGe alloys are disclosed that compensate for dangling bonds in the alloy to reduce substantially localized defect density.

On the other hand, as a method other than the above-described substantial improvement in film quality, improvement in characteristics of a solar cell containing amorphous SiGe is being studied.

One example is disclosed in US Pat.
No. 4,429, discloses a method using a so-called buffer layer for providing a gradient of the bandwidth at the junction interface between the p-type semiconductor and / or the n-type semiconductor layer and the i-type semiconductor layer.

As another method, there is disclosed a method of providing a so-called gradient layer for improving the characteristics by distributing the composition in the intrinsic layer by changing the composition ratio of silicon and germanium. For example, in U.S. Pat. No. 4,816,082, the band gap of the i-layer at the portion in contact with the first valence electron controlled semiconductor layer on the light incident side is widened, and gradually increases toward the center. A method is disclosed in which the band gap is narrowed and the band gap is gradually widened toward the second semiconductor layer in which valence electrons are controlled. According to this method, carriers generated by light can be efficiently separated by the action of an internal electric field, and the film characteristics are improved.

As a method of continuously forming a semiconductor functional deposition film used for a photovoltaic element or the like on a substrate, an independent film forming chamber for forming various semiconductor layers is provided, and each of these film forming chambers is provided. Are connected by a load lock method via a gate valve, and a method is known in which a substrate is sequentially moved to each film forming chamber to form various semiconductor layers.

In particular, as a method for significantly improving mass productivity, US Pat. No. 4,400,409 discloses a continuous plasma CVD method employing a roll-to-roll method. I have. According to this method, a long strip-shaped member is used as a substrate, and while a conductive semiconductor layer required in a plurality of glow discharge regions is deposited and formed, the substrate is continuously transported in its longitudinal direction. It describes that an element having a semiconductor junction can be continuously formed.

According to this method, it takes several hours to form a semiconductor layer on a belt-shaped substrate having a length of several hundred meters, and a uniform and reproducible discharge state is maintained and controlled. It is necessary to form a layer. Therefore, it is necessary to develop a technique for continuously forming a high-quality and uniform semiconductor deposition film continuously and with high yield over the entire length of the long band-shaped substrate from the beginning to the end.

When a graded bandgap thin film semiconductor layer of, for example, amorphous silicon germanium is used as the i-type semiconductor layer of the photovoltaic element, silane (Si)
A semiconductor film having a desired conductivity type can be obtained by mixing source gases such as H ₄ ) and germane (GeH ₄ ) and performing glow discharge decomposition. However, in order to form a high-quality amorphous silicon germanium thin film having a desired band gap, the dependence of the film formation conditions on the film is essentially very large, and the film formation condition is very small against slight deviation (shift). Because of its sensitivity, if it deviates from the optimum formation conditions for some reason, the performance of the photovoltaic element such as the fill factor tends to be immediately reduced.

In a typical structure of a conventional discharge vessel, the total area of the grounded anode electrode including the substrate is:
In many cases, the area is very large compared to the area of the cathode electrode. In such a cathode electrode, most of the input high-frequency power is consumed in the vicinity of the cathode electrode. Excitation and decomposition reactions of the material gas become active only in the part, and the thin film formation rate increases only on the high-frequency power input side, that is, near the cathode electrode. High-frequency power to the substrate side is not supplied sufficiently large, and it is difficult to form a semiconductor thin film at a desired high deposition rate, and it is very difficult to obtain a good semiconductor thin film. Met.

Furthermore, a typical structure of a conventional discharge vessel,
That is, in a discharge vessel having a structure in which the entire area of the grounded anode electrode including the substrate is much larger than the area of the cathode electrode, a positive potential (bias) is applied to the cathode electrode using a direct current (DC) power supply or the like. Techniques are in place. However, in such a system, a DC power supply is used.
As a result of using the following means, the DC current flows through the plasma discharge, so if the DC voltage bias is increased, abnormal discharge such as sparks will occur. It was very difficult to maintain the discharge. Therefore, it was unclear whether the effect of applying a DC voltage to the plasma discharge was effective. This is because the DC voltage and the DC current cannot be separated. That is, means for effectively applying only a DC voltage to plasma discharge has been desired.

The i-type semiconductor layer of the photovoltaic element is often set to a very thin thickness of several hundred to several hundreds of mm at most from the viewpoint of element characteristics. At the time of element formation, uniformity of the layer thickness, adhesion of the film,
The composition, the uniformity of the characteristics, and the reproducibility not only affect the characteristics of the device, but also greatly affect the yield of the device.

Therefore, in order to form a non-single-crystal thin film which is uniform in space and time and has good reproducibility, the discharge stability over a long period of time and the reproducibility and uniformity are improved. There is a need for a forming method and a forming apparatus. In order to improve the throughput of the equipment and reduce costs, while maintaining the quality of the semiconductor thin film,
It is desired to develop a forming method and a forming apparatus capable of realizing a high deposition rate. Furthermore, the basic characteristics of the i-type semiconductor layer greatly affect the characteristics of the photovoltaic element electrically and optically. In particular, in the stacked photovoltaic element, the precise optical band gap and the precise Fermi level Because control is needed,
There is a need for a method and apparatus for forming a high-quality i-type semiconductor layer uniformly and continuously with good reproducibility.

[0025]

DISCLOSURE OF THE INVENTION The present invention is intended to provide a photoelectric conversion device having high photoelectric conversion efficiency, high quality, excellent uniformity, and excellent reproducibility over a large area on a continuously moving belt-like member.
Further, it is an object of the present invention to provide a forming method and a forming apparatus capable of producing a large amount of photovoltaic elements with few defects.

[0026]

Means for Solving the Problems The present inventor has solved the above-mentioned problems in the prior art and made intensive studies to achieve the object of the present invention.

According to the photovoltaic device forming apparatus of the present invention, a first conductive type semiconductor layer, an i-type semiconductor layer, and a second conductive layer made of a non-single crystal are formed on a continuously moving conductive strip. In an apparatus for forming a photovoltaic element having one or more sets of structures in which type semiconductor layers are sequentially stacked, a discharge vessel used for forming the i-type semiconductor layer includes a high-frequency power application electrode (hereinafter referred to as a cathode electrode) provided in a discharge space. ) In the discharge space is larger than the surface area of the entire anode electrode including the surface area of the strip-shaped member in the discharge space, and the potential of the cathode electrode (hereinafter, referred to as self-bias) when the glow discharge occurs is caused by the strip-shaped member. A positive potential of +30 V or more with respect to the grounded anode electrode,
In addition, a part of the fin-shaped cathode electrode (hereinafter, referred to as a “strip-shaped electrode”) is provided in a plurality in a direction perpendicular to the transport direction of the strip-shaped member, and the intervals between the strip-shaped electrodes are adjacent to each other. And a cathode structure having a sufficient interval to maintain and maintain a discharge between the electrodes, and a material gas used for forming the i-type semiconductor layer is introduced into the discharge space between the adjacent electrodes from between adjacent adjacent electrodes. A mechanism that flows in a direction (width direction of the band-shaped member) perpendicular to the moving direction of the band-shaped member along the strip-shaped electrode, applies high-frequency power to the cathode electrode, and decomposes the material gas by plasma discharge; It is characterized by having.

Further, the apparatus for forming a photovoltaic element according to the present invention comprises:
When a plurality of types of material gases are introduced into the discharge space between the separated electrodes, a gas supply unit is provided which guides the plurality of types of material gases to the discharge space independently of each other.

The apparatus for forming a photovoltaic element of the present invention having the above-described structure has the following functions.

(1) The discharge vessel used for forming the i-type semiconductor layer is such that the surface area in the discharge space of a high-frequency power application electrode (hereinafter referred to as a cathode electrode) provided in the discharge space includes the surface area of the strip-shaped member. It is larger than the surface area of the entire electrode in the discharge space, and the potential of the cathode electrode (hereinafter referred to as “self-bias”) when a glow discharge occurs is +3 with respect to the grounded anode electrode including the strip-shaped member.
A positive electrode having a positive potential of 0 V or more can be maintained, and a plurality of fin-shaped cathode electrodes (hereinafter, referred to as “cut-off electrodes”) are provided in plural in a direction perpendicular to the transport direction of the belt-like member. The distance between each of the electrode-shaped electrodes is limited to the vicinity of the cathode electrode, which is a drawback in the conventional device because of having a cathode structure having a sufficient distance for maintaining and maintaining a discharge between the adjacent electrode-shaped electrodes. Excitation and decomposition reaction of the material gas are not promoted only in the part where the material gas is excited, decomposition reaction is promoted in the entire discharge space, and rather on the anode electrode side including the band-shaped member, and is relatively high. With a deposition rate, a thin film can be efficiently deposited on the belt-shaped member. That is, the amount of high-frequency power supplied to the cathode is properly adjusted, and the high-frequency power supplied is used more effectively to efficiently excite and decompose the material gas introduced into the discharge space. A single-crystal semiconductor thin film can be formed on the belt-shaped member uniformly and with good reproducibility at a relatively high deposition rate.

(2) The material gas used for forming the i-type semiconductor layer is introduced into the discharge space between the adjacent strip electrodes from the space between the adjacent strip electrodes, and the belt-like member moves along the cut electrodes. A direction is perpendicular to the direction (the width direction of the strip-shaped member), and a mechanism is provided for applying high-frequency power to the cathode electrode to decompose the material gas by plasma discharge. A plurality of adjacent plasma spaces can be provided.
As a result, a long film-forming space (that is, a chamber length) required for forming the i-type graded band gap semiconductor layer in the roll-to-roll method, which is a drawback in the conventional technology, can be significantly reduced. A forming device is obtained.

(3) When a plurality of types of material gases are introduced into the discharge space between the separated electrodes, a gas supply means for independently introducing the plurality of types of material gases into the discharge space is provided. A gas having an arbitrary composition ratio can be freely introduced along the transport direction of the belt-shaped member. As a result, a deposited film whose composition is precisely controlled in the film thickness direction on the belt-shaped member can be formed.

That is, by using the apparatus of the present invention, for example, a silicon germanium graded band gap semiconductor film whose composition is precisely controlled in the thickness direction can be formed.
The apparatus can be formed with a more compact apparatus than before and with reduced consumption of material gas. Here, a compact device refers to a device with a reduced number of chambers or a device with a reduced chamber length.

According to the method of forming a photovoltaic element of the present invention, a first conductive type semiconductor layer, an i-type semiconductor layer and a second conductive layer made of a non-single crystal are formed on a continuously moving conductive strip. In a method for forming a photovoltaic device having at least one set of structures in which type semiconductor layers are sequentially stacked, a high-frequency power application electrode (hereinafter referred to as a cathode electrode) provided in a discharge space is used as a discharge vessel for forming the i-type semiconductor layer. ) Has a structure in which the surface area in the discharge space is larger than the surface area of the entire anode electrode including the surface area of the strip-shaped member in the discharge space, and the potential of the cathode electrode (hereinafter referred to as self-bias) at the time of occurrence of a glow discharge. A part of the fin-shaped cathode electrode, which can maintain a positive potential of +30 V or more with respect to a grounded anode electrode including the strip-shaped member. A plurality of cathodes are provided perpendicular to the direction in which the belt-shaped member is conveyed, and the gaps between each of the gap-shaped electrodes have a sufficient interval for generating and maintaining a discharge between adjacent gap-shaped electrodes. Using a device for forming a photovoltaic element provided with a discharge vessel having a structure, a material gas used for forming an i-type semiconductor layer is introduced into the discharge space between the adjacent electrodes from between adjacent adjacent electrodes, By flowing high-frequency power to the cathode electrode and decomposing the material gas by plasma discharge while flowing in a direction perpendicular to the moving direction of the band-shaped member (width direction of the band-shaped member) along the strip-shaped electrode, It is characterized in that an i-type semiconductor layer is formed.

Further, the method of forming a photovoltaic element of the present invention comprises:
By providing a plurality of types of material gases to be introduced into the discharge space between the cut-off electrodes and guiding them independently to the discharge space, the composition ratio (mixing ratio) of the material gas introduced along the moving direction of the strip-shaped member And forming the i-type semiconductor layer.

The method for forming a photovoltaic element according to the present invention having the above-described structure has the following operation.

(1) By using the apparatus having the above-described configuration, a discharge state that is uniform and has good reproducibility over a long film formation time such as forming a semiconductor layer on a belt-shaped member having a length of several hundred meters. Maintain control and
It is possible to form a semiconductor layer whose composition is controlled.

(2) According to the above (1), a high-quality and uniform semiconductor deposited film can be formed continuously and with high yield over the entire length of the long band-shaped member from the start to the end.

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the apparatus and method for forming a photovoltaic element according to the present invention, the following configuration is a preferred embodiment.

In the device of the present invention, the material of the cathode electrode may be stainless steel and its alloys, aluminum and its alloys, etc. In addition, any other materials having conductivity may be used. Need not be. The same applies to the anode electrode material.

In the apparatus for continuously manufacturing a photovoltaic element according to the present invention, the belt-shaped member is successively moved in the longitudinal direction while sequentially passing through the film formation space of the photovoltaic element, and the photovoltaic element is continuously formed. This is an apparatus for continuously manufacturing, or an apparatus for sequentially manufacturing a stacked photovoltaic element by sequentially passing through a film forming space of a plurality of photovoltaic elements. Further, the device of the present invention has a structure in which the potential (self-bias) of the cathode electrode installed in the glow discharge space can maintain a positive potential with respect to the ground (anode) electrode including the strip-shaped member, In addition, a plurality of the fin-shaped or block-shaped partition electrodes are provided in parallel or perpendicular to the transport direction of the band-shaped member, and the interval between the partition electrodes is such that a discharge between the adjacent partition electrodes is generated. This is a device having a cathode structure with a sufficient space to maintain the occurrence.

According to the present invention, the surface area of the space in contact with the discharge of the high-frequency power application cathode electrode provided in the glow discharge space is made larger than the surface area of the whole grounded electrode (anode electrode) including the strip-shaped member in the discharge space. In addition, by adjusting the applied high frequency power, the potential (self-bias) of the cathode electrode at the time of forming a semiconductor thin film by generating a glow discharge,
The method is characterized in that an i-type semiconductor thin film is deposited while maintaining the voltage at +30 V.

Further, in the present invention, a plurality of the cut-off electrodes are provided in the transport direction of the strip-shaped member, and the interval between the cut-off electrodes is sufficient to generate and maintain a discharge between the adjacent cut-off electrodes. By providing an interval, a relatively large positive potential can be generated and maintained at the cathode electrode by a self-bias. This configuration is different from a bias application method using a separately provided direct current (DC) power supply or the like, and can suppress occurrence of abnormal discharge due to sparks or the like, thereby stably generating and maintaining discharge. In addition, since a part of the cathode electrode where the positive self-bias is generated, that is, the tip of the cut-off electrode is relatively close to the band-shaped member, the generated relatively large positive potential is generated. A bias can be efficiently and stably applied to the deposited film of the belt-shaped member via the discharge space. This configuration is a method of simply shortening the distance between the cathode and the substrate in the cathode electrode structure in the conventional typical device, that is, in the parallel plate type cathode electrode structure in which the cathode electrode area is smaller than the anode (ground) electrode area. And a self-bias potential which is clearly different from a method of applying a DC voltage to the cathode by using a DC power supply in combination with the DC power supply.

The present invention is characterized in that an i-type non-single-crystal semiconductor is formed by the above-described apparatus, and the cathode electrode is maintained at a positive potential, so that a positive electrode is formed on the strip-shaped deposition film. Since the bias is applied in the direction of irradiating the charged ions, the ions present in the plasma discharge are more efficiently applied in the direction of the band-shaped member, and the energy is effectively applied to the surface of the deposited film by so-called ion bombardment. it can. As a result, even at a relatively high deposition rate, the relaxation of the structure of the film is promoted, the quality and densification of the film are improved, and a high-quality semiconductor thin film can be relatively easily obtained. In forming an i-type non-single-crystal semiconductor thin film, the value of the above-described cathode electrode greatly affects the characteristics of the thin film to be formed, and a high-quality i-type semiconductor layer can be formed at a relatively high deposition rate with good uniformity and reproducibility. To realize well,
As described above, the thin film is deposited while maintaining the potential of the cathode electrode at +30 V or more, preferably +100 V or more, and more preferably +150 V or more.

Further, the present invention is characterized in that the flow direction of the material gas introduced into the discharge space flows in a direction perpendicular to the conveying direction of the belt-shaped member, that is, in the width direction of the band-shaped member. The material gas to be introduced flows at right angles to the transport direction of the band-shaped member between the plurality of the strip-shaped electrodes arranged in parallel to the transport direction of the band-shaped member. By changing the composition of the material gas introduced between the separated electrodes in the transport direction of the strip-shaped member, a deposited film whose composition is precisely controlled in the film thickness direction can be formed in the strip-shaped member.

Hereinafter, an apparatus for forming a photovoltaic element according to the present invention will be described.

FIG. 1 is a schematic sectional view showing the structure inside the discharge vessel constituting the forming apparatus of the present invention. FIG.
FIG. 2 is a schematic bird's-eye view showing an example of the cathode electrode shown in FIG. 1. In FIG. 1, reference numeral 1000 denotes a conductive belt-like member;
001 is a vacuum container, 1002 is a cathode electrode, 1003
A strip-shaped electrode, 1004 is a ground (anode) electrode, 1
005 is a lamp heater, 1006 is an exhaust port, 1007
Denotes a gas introduction pipe, 1008 denotes a gas gate, 1009 denotes an insulating insulator, and 1010 denotes a discharge space.

The cathode electrode 1002 in FIG. 1 has the same structure as the cathode electrode example shown in FIG. 2, and is installed on a ground (anode) electrode 1004 in a state where it is electrically insulated by an insulating insulator 1009. Have been. The conductive band-shaped member 1000 supports the space above the cathode electrode 1002 by arrows without being physically in contact with the cathode electrode located below and the lamp heater 1005 located above while being supported by a plurality of magnet rollers (not shown). Move in the direction indicated. The material gas is a gas introduction pipe 1007
And passes between the belt-shaped member and the cathode electrode in a direction perpendicular to the transport direction of the belt-shaped member, and is exhausted from an exhaust port 1006 by a vacuum pump (not shown). SUS316 was used as a cathode electrode and anode electrode material. A high frequency is applied from a high frequency electrode (not shown) to the cathode electrode, and the discharge region of the glow discharge generated is a plurality of grounded strip-shaped electrodes 1 which are a part of the cathode electrode.
003 and a space between the strip-shaped member and the cathode electrode, and a region enclosed by the upper conductive strip-shaped member 1000.

When a discharge vessel having such a structure is used,
The ratio of the area of the cathode electrode to the area of the grounded anode electrode including the strips is clearly greater than one. Further, the closest distance between the strip-shaped member 1000 and a fin-shaped or block-shaped cut-off electrode 1003 which is a part of the cathode electrode (l in FIG. 1)
It is effective that 1) be within the range of 5 cm or less. Further, the interval between the plurality of threshold electrodes 1003 provided has a sufficient interval for generating and maintaining the discharge, and the appropriate interval (12 in FIG. 2) should be within a range of 3 cm or more and 10 cm or less. It is effective.

FIG. 10 is a schematic sectional view showing an example of a conventional discharge vessel having a cathode electrode. As is apparent from FIG. 10, the cathode electrode 200 in contact with the discharge space
2 has a smaller structure than the total surface area of the grounded anode electrode 2004 including the conductive strip member 2000 which is also in contact with the discharge space. That is, the ratio of the area of the cathode electrode to the area of the grounded anode electrode including the strip-shaped member is clearly smaller than 1.

FIGS. 3 to 7 are schematic plan views of the cathode electrode viewed from the side of the belt-like member, showing the positions where the material gas inlet and exhaust ports are provided and the flow of the material gas in the cathode electrode of FIG. FIG. The arrows shown in the figure indicate the direction in which the material gas flows.

In order to precisely control the composition of the deposited film formed on the conductive strip 1000 in the thickness direction,
The material gas is introduced into the discharge space between the adjacent strip electrodes 1003, and flows between the strip electrodes 1003 at right angles to the moving direction of the strip member 1000 (in the width direction of the strip member 1000). The composition ratio (mixing ratio) of the supplied material gas is adjusted along the moving direction of the belt-shaped member 1000.

Supply position of material gas, that is, gas introduction pipe 1
The position where 007 is provided may be on the cathode electrode facing the strip-shaped member (FIG. 3) or may be on a plate connecting between adjacent strip-shaped electrodes (FIG. 4). The position of the exhaust port may be provided on the cathode electrode facing the strip-shaped member (FIG. 3) or may be provided on a plate connecting the adjacent strip-shaped electrodes (FIG. 4). If the flow of the material gas in the discharge space flows at right angles (in the width direction of the belt-like member) to the moving method of the belt-like member along the threshold electrode, there are no restrictions on the introduction position of the material gas and the exhaust port position.

FIGS. 5 to 7 show a material gas inlet and a gas outlet designed in consideration of the uniformity of various characteristics of the deposited film in the width direction of the band-shaped member when the band-shaped member is wide. It is the typical sectional view of the cathode electrode which saw the position and was seen from the belt-like member side. The arrows shown in the figure indicate the direction in which the material gas flows. In order to prevent the distance between the material gas introduction position and the exhaust port from becoming too wide, several sub-positions of the material gas introduction position or the exhaust port are arranged in the conveying direction of the strip-shaped member (FIG. 5), or in the adjacent discharge space. The uniformity of the plasma in the width direction of the strip-shaped member in the discharge space is increased by alternately or staggering the arrangement (FIG. 6), or by alternately changing the flow of the material gas in the adjacent discharge space (FIG. 7). The composition of the deposited film formed on the belt-shaped member is made uniform in the width direction.

FIGS. 8 and 9 are conceptual schematic views showing a method of controlling the flow rate of the material gas introduced into the discharge space.

FIG. 8 is a diagram showing a method of introducing and controlling a material gas for forming a deposited film having a uniform composition in the film thickness direction. The flow rate of the material gas supplied from the gas cylinder 1012 is controlled by the mass flow controller 1011, the necessary gas is mixed, and the gas introduction pipe 100 is provided near the cut-off cathode electrode by piping.
7 to the discharge space. At this time, the material gas is equally distributed by branching the pipe into equal conductances according to the number of introduction points, and introduced into the discharge space from between the fin-shaped electrodes.

FIG. 9 is a diagram showing a method of introducing and controlling a material gas for forming a deposited film having a composition gradient in the film thickness direction. That is, in order to form a composition gradient, the mixing ratio (or flow rate ratio) of a plurality of material gases introduced into the discharge space is changed in the moving direction of the belt-shaped member. Gas cylinder 1
After controlling the flow rate of the material gas supplied from 012 through the mass flow controller 1011 for each gas type, the material gas is guided to the vicinity of the cut-off cathode electrode by piping. The pipe is arranged in parallel to the transport direction of the strip-shaped member, guided to the gas mixing unit 1013 through a small hole, and mixed with another gas similarly guided. The material gas guided to each gas mixing section is branched (designs the conductance of the branch pipe) and distributed according to the flow rate guided to the gas mixing section by piping through the mass flow controller 1011. The mixed gas is introduced into the discharge space from another small hole provided in the gas mixing space through a gas introduction tube 1007 provided between the cathode electrodes.

The gap (11 in FIG. 1) between the strip-like electrode and the strip-like member promotes mutual diffusion of gas between adjacent discharge spaces, and is important for forming a smooth composition gradient in the thickness direction of the deposited film. It is. When l1 is large, mutual diffusion is promoted, but independence between adjacent discharges is reduced.

[0059]

EXAMPLES Hereinafter, the method for forming a photovoltaic device according to the present invention will be described in detail with reference to specific examples, but the present invention is not limited to these examples.

(Embodiment 1) In this embodiment, the discharge vessel shown in FIG. 1 is replaced with a roll-to-roll shown in FIG.
l) A single cell type photovoltaic element was manufactured by using it as a container for forming an i-type layer in a continuous plasma CVD apparatus of the system. At that time, the cathode structure in the discharge vessel of FIG.
The dimensions and arrangement were as follows.

The closest distance (11 in FIG. 1) between the strip-shaped member and the strip-shaped electrode which is a part of the cathode electrode is 0.1.
It was 5 cm. Eighteen strip electrodes were provided, and the interval between the strip electrodes (12 in FIG. 1) was 5 cm (that is, the cathode electrode length was 105 cm). The length in the width direction of the strip-shaped member of the strip electrode was 50 cm. The ratio of the cathode area to the entire grounded anode area including the conductive strip was 3.0 times. The material gas was evenly distributed between the separated electrodes and supplied. At that time, the arrangement of the gas introduction port and the exhaust port was the pattern shown in FIG.

The apparatus for manufacturing a single-type photovoltaic element shown in FIG. 11 (FIG. 11) includes vacuum vessels 301 and 302 for feeding and winding the belt-like member 101 and a vacuum vessel 601 for producing the first conductive type layer. , I-type layer forming vacuum container 10
0, a second conductive type layer forming vacuum container 602 was connected via a gas gate. That is, the i-type layer forming vacuum container 100 is an i-type layer forming container having the cathode electrode configured as described above.

Hereinafter, a method of manufacturing the single type photovoltaic element shown in FIG. 12 using the manufacturing apparatus shown in FIG. 11 will be described. In FIG. 12, reference numeral 4001 denotes a SUS substrate, 4
002 is an Ag thin film, 4003 is a ZnO thin film, 4004 is a first conductivity type layer, 4005 is an i-type layer, 4006 is a second conductivity type layer, 4007 is ITO, and 4008 is a current collecting electrode.

Each layer was continuously produced by the following procedure to form a single type photovoltaic element (element-Example 1). Table 1 shows the manufacturing conditions of each layer.

(1) The vacuum vessel 301 having a substrate sending-out mechanism is sufficiently degreased and washed to form a lower electrode.
By sputtering, a silver thin film is formed to a thickness of 100 nm and ZnO
SUS430BA strip-shaped member 101 (400 mm wide x 200 m long x 0.13 m thick)
m), the wound bobbin 303 is set, the strip-shaped member 101 is passed through a gas gate, and a vacuum container 30 having a strip-shaped member winding-up mechanism via each non-single-crystal layer forming vacuum container.
2 and the tension was adjusted to the extent that there was no slack.

(2) Each vacuum vessel 301, 601, 10
0, 602 and 302 are 1 × 10 ^{−4 by} a vacuum pump (not shown).
Vacuum was drawn to Torr or less.

(3) The gate gas introduction pipe 13 is connected to the gas gate.
1 n, 131, 132, and 131p, H ₂ was supplied as a gate gas at a flow rate of 700 sccm,
The belt-shaped member 101 was heated to 350 ° C., 350 ° C., and 250 ° C. by n, 124, and 124p, respectively. Then, SiH ₄ gas was supplied at a flow rate of 40 sccm and P
50 sccm of H ₃ gas (2% H ₂ diluted product), 200 sccm of H ₂ gas, gas introduction pipes 104a, 104b, 10
4c, the SiH ₄ gas was 100 sccm each, the H ₂ gas was 500 sccm each, and the SiH ₄ gas was 10 sccm and the BF ₃ gas (2% H ₂ diluted product) was 10 sccm from the gas introduction pipe 606.
0 sccm and 500 sccm of H ₂ gas were introduced.

(4) The pressure in the vacuum vessel 301 was adjusted by the conductance valve 307 so as to become 1.0 Torr by the pressure gauge 314. The pressure inside the vacuum vessel 601 was adjusted with a conductance valve (not shown) so that the pressure became 1.5 Torr with a pressure gauge (not shown). The pressure inside the vacuum vessel 100 was adjusted with a conductance valve (not shown) so that the pressure became 1.8 Torr by a pressure gauge (not shown). Vacuum container 60
The pressure in 2 was adjusted with a conductance valve (not shown) so that the pressure in the pressure gauge became 1.6 Torr with a pressure gauge (not shown). When the pressure in the vacuum vessel 302 is 1.0 Torr by the pressure gauge 315,
Was adjusted by the conductance valve 308 so that

(5) RF power of 500 W is introduced to the cathode electrode 603, and 2 RF power is applied to the cathode electrode 107.
00W, and RF power of 60
0W was introduced.

(6) The belt-like member 101 is transported in the direction indicated by the arrow in FIG. 11 and the first conductive type layer, i, is formed on the belt-like member.
A mold layer and a second conductivity type layer were produced.

(7) ITO (In ₂ O ₃ + SnO ₂ ) is applied as a transparent electrode on the second conductivity type layer by vacuum evaporation to a thickness of 80 nm.
m, and Al as a collecting electrode by vacuum evaporation.
μm was deposited.

Through the above steps (1) to (7), the photovoltaic device of the present example (device-Example 1) was manufactured.

[0073]

[Table 1]

(Comparative Example 1) In this example, the structure of the cathode electrode 603 in the vacuum vessel 100 and the structure of the cathode electrode 604 in the vacuum vessel 602 were changed to the parallel plate type cathode electrode structure shown in FIG. Different from 1. At that time, the cathode structure had the following dimensions and arrangement.

The size of the cathode electrode is 50 cm wide ×
The length was 130 cm. The ratio of the cathode area to the entire grounded anode area including the conductive strip was 0.6 times. The material gas flowed through the discharge space on the cathode electrode in the moving direction of the belt-shaped member.

The conditions for forming each layer were set to the values shown in Table 2.

The other points were the same as in Example 1, and a single type photovoltaic element (element-ratio 1) was formed.

[0078]

[Table 2]

Example 1 (Element-Example 1) and Comparative Example 1
The conversion efficiency, characteristic uniformity, and yield of the photovoltaic element manufactured in (element-ratio 1) were evaluated.

The current-voltage characteristics were determined by cutting out the central portion in the width direction and an area of 5 cm square from the end (5 cm from the end) every 10 m of the band-shaped member, and placed under AM-1.5 (100 mW / cm ² ) light irradiation. The photoelectric conversion efficiency was measured and evaluated. The yield was measured by measuring the shunt resistance of the cut-out 5 cm square element in the dark state, and counting those with a resistance value of 1 × 10 ³ Ω · cm ² or more as non-defective products, expressing the ratio in the total number as a percentage, and evaluating it. did.

Table 3 shows the above evaluation results. Each value of Example 1 (element-actual 1) shown in Table 3 is a value normalized by setting the average value of each characteristic of Comparative Example 1 (element-ratio 1) to 1.00.

[0082]

[Table 3]

As can be seen from Table 3, each element of (element-actual 1) is generally improved as compared with (element-ratio 1). In particular, it was confirmed that the open-circuit voltage was improved. It was found to be improved by a factor of 05.

As shown in Table 3, the photovoltaic element of Comparative Example 1 (element-ratio 1) was changed to Example 1 (element-actual 1).
Is excellent in conversion efficiency, and it has been found that the photovoltaic element manufactured by the manufacturing method of the present invention has excellent characteristics, and the effect of the present invention has been demonstrated.

The uniformity of the characteristics in the width direction of the belt-shaped member was determined in Example 1.
(Element-Actual 1), Photovoltaic elements on the belt-shaped member produced in Comparative Example 1 (Element-Ratio 1) were cut out every 10 m at the center and the end (5 cm from the end) in the width direction with an area of 5 cm square. ,
The device was placed under AM-1.5 (100 mW / cm ² ) light irradiation, the photoelectric conversion efficiency was measured, and the width distribution of the photoelectric conversion efficiency was evaluated. Table 4 shows the variation (expressed in%) of the average value of each characteristic value at the center and the end in the width direction.

[0086]

[Table 4]

From Table 4, it can be seen that the photovoltaic element of Example 1 (Element-Comparative 1) is superior to the photovoltaic element of Comparative Example 1 (Element-Comparative 1) in the uniformity of the characteristics. The single type photovoltaic element manufactured by the manufacturing method of the present invention was found to have excellent characteristics, and the effect of the present invention was demonstrated.

(Embodiment 2) In this embodiment, the cathode electrode in the i-type layer forming vacuum vessel 100 is the same as in Embodiment 1,
The arrangement of the material gas introduction port and the exhaust port is shown in FIG. 6, and the material gas introduction method and the control method are the same as those shown in FIG. 9 except that the composition controlled i-type a-SiGe ₄ : H deposition film is made of SUS4.
It was produced on a belt-shaped member made of 30BA (length 100 m).

In the following description, the discharge space between the separated electrodes is defined as (1),
(2),..., (16), (17). The distance between the strip-shaped electrode and the band-shaped member (11 in FIG. 1) was 0.5 cm.

As a material gas supplied between the separated electrodes, SiH ₄ , GeH ₄ , and H ₂ gas were used. The GeH ₄ gas flows between (1) discharge electrodes (discharge space) located at the center.
The supply amount was reduced from 1) to both ends, and set to zero at both ends (1) and (17). On the other hand, the SiH ₄ gas is supplied between (1) and (1) between the cut-off electrodes located at both ends (discharge space).
The supply was set to decrease from 7) to (11) in the center. H ₂ was supplied evenly between the fins.

Table 5 shows the conditions for forming the i-type layer.

[0092]

[Table 5]

A part of the center and the end in the width direction of the strip-shaped member on which the deposited film was formed was cut out every 10 m, and the
Composition analysis in the thickness (depth from the surface) direction of the deposited film was performed using MS. As a result, a depth profile shown by a solid line in FIG. 16 was obtained, and it was found that a band profile almost as shown in FIG. 17 was formed.

(Comparative Example 2) In this example, the cathode electrode structure in the i-type layer forming vacuum vessel 100 was changed to the parallel-plate cathode electrode structure shown in FIG. 10 (conventional type: in this case, a conductive strip member was used). (The ratio of the cathode area to the entire grounded anode area is 0.6 times), and the i-type a-S whose composition is controlled in a stationary state without moving the belt-shaped member.
An iGe ₄ : H deposited film was formed on a SUS430BA strip.

As shown in Table 6, the composition of the i-type layer was controlled by a method of smoothly changing the mixing ratio of SiH ₄ and GeH ₄ according to the elapse of the film formation time.

[0096]

[Table 6]

The strip-shaped member on which the deposited film was formed was cut out at an arbitrary position, and the composition was analyzed in the same manner as in Example 2. As a result, a smooth depth profile indicated by a broken line in FIG. 16 was obtained, which is substantially shown in FIG. It was found that the same band profile as in Example 2 was formed.

Accordingly, it has been clarified that the composition of the deposited film in the thickness direction can be controlled by the apparatus and method of the present invention.

It has also been confirmed that the composition and the thickness direction of the deposited film can be formed uniformly in the width direction of the strip-shaped member by the apparatus and method of the present invention.

Further, the depth profile of the deposited film produced in Example 2 shows a smooth change similarly to the deposited film produced in Comparative Example 2, and the deposited film of Example 2 has a band profile of a smooth change. Are formed. That is, a-SiGe: H is obtained by the apparatus and method of the present invention.
It was found that the composition control in the thickness direction of the deposited film such as a graded band gap structure can be smoothly controlled.

Example 3 In this example, the a-SiGe: H graded band gap i-type layer shown in Example 2 was adopted, and the single type photovoltaic element shown in FIG. It was manufactured under the manufacturing conditions shown. The photovoltaic element manufactured in this example is referred to as (element-real 3).

The other points were the same as in the first embodiment.

[0103]

[Table 7]

(Comparative Example 3) In this example, a-SiGe: H
The graded bandgap i-type layer is formed using a-SiGe:
H flat bandgap i-type layer and a-S sandwiching it
As a three-layer structure of i: H flat band gap i-type (first and second) buffer layers, the single-type photovoltaic element shown in FIG. 14 was manufactured under the manufacturing conditions shown in Table 8. The photovoltaic element manufactured in this example is referred to as (element-ratio 3).

The apparatus for producing the i-type layer has a parallel plate type cathode electrode structure shown in FIG. 10 (the ratio of the cathode area to the whole grounded anode area including the conductive strip member is 0.6 times). An apparatus similar to that shown in FIG. 11 in which the above-described three-layer film forming vacuum vessel was arranged was used.

The other points were the same as in the first embodiment.

[0107]

[Table 8]

Example 3 (Element-Real 3) and Comparative Example 3
The conversion efficiency, characteristic uniformity, and yield of the photovoltaic element manufactured in (element-ratio 3) were evaluated.

The current-voltage characteristics were obtained by cutting out the central part in the width direction and an area of 5 cm square from the end (5 cm from the end) every 10 m of the band-shaped member, and placed under AM-1.5 (100 mW / cm ² ) light irradiation. The photoelectric conversion efficiency was measured and evaluated. The yield was as in Example 3 (element-actual 3), Comparative Example 1 (element-ratio 3)
Cut out the photovoltaic element on the belt-shaped member prepared in the above at an area of 5 cm square at intervals of 10 m, and measure the shunt resistance in the dark state. If the resistance value is 1 × 10 ³ Ω · cm ² or more, a good product And the ratio in all the numbers was expressed as a percentage and evaluated.

Table 9 shows the above evaluation results. Each value of Example 3 (Element-Real 3) shown in Table 9 is a value normalized by setting the average value of each characteristic of Comparative Example 3 (Element-Comparative 3) to 1.00.

[0111]

[Table 9] From Table 9, it can be seen that (element-actual 3) has overall improved characteristics as compared to (element-ratio 3), and that the open-circuit voltage is particularly improved, resulting in a conversion efficiency of 1.05 times. It was found to improve.

As shown in Table 9, the photovoltaic element of Comparative Example 3 (element-ratio 3) was replaced with Example 3 (element-actual 3).
Is excellent in conversion efficiency, and it has been found that the photovoltaic element manufactured by the manufacturing method of the present invention has excellent characteristics, and the effect of the present invention has been demonstrated.

The uniformity of the characteristics in the width direction of the belt-like member was determined in Example 3.
(Element-Real 3), Photovoltaic elements on the belt-shaped member produced in Comparative Example 3 (Element-Comparative 3) were cut out at an interval of 10 m at an area of 5 cm square at the center and the end (5 cm from the end) in the width direction. ,
The device was placed under AM-1.5 (100 mW / cm ² ) light irradiation, the photoelectric conversion efficiency was measured, and the width distribution of the photoelectric conversion efficiency was evaluated. Table 10 shows the variation (expressed in%) of the average value of each characteristic value at the center and the end in the width direction.

[0114]

[Table 10]

From Table 10, it can be seen that the photovoltaic element of Example 3 (Element-Real 3) is more excellent in the uniformity of the characteristics than the photovoltaic element of Comparative Example 3 (Element-Comparative 3). The single-cell photovoltaic element manufactured by the manufacturing method of the present invention was found to have excellent characteristics, and the effect of the present invention was demonstrated.

(Embodiment 4) In this embodiment, the forming container shown in FIG. 1 is roll-to-roll as shown in FIG.
o) A triple cell type photovoltaic element shown in FIG. At that time, the cathode structure in the forming container of FIG. 1 had the following dimensions and arrangement.

The closest distance (11 in FIG. 1) between the strip-shaped member and the strip-shaped electrode which is a part of the cathode electrode is 0.5.
cm. The interval (12 in FIG. 1) between the plurality of arranged strip electrodes was 5 cm. The ratio of the cathode area to the entire grounded anode area including the conductive strip was 3.0 times.

A continuous plasma CVD apparatus (not shown) adopting a roll-to-roll method as shown in FIG. 11 is a vacuum vessel for producing a first conductive type layer shown in FIG. 601, the i-type layer forming vacuum container 100, and the second conductive type layer forming vacuum container 602 are connected via a gas gate as one set, two more sets are added, and a total of three sets are repeated in series. It is a device of the configuration arranged in. And the above-mentioned formation container was installed in all the i-type layer formation containers.

Using the apparatus having the above configuration, the triple cell type photovoltaic element shown in FIG. 13 was manufactured under the manufacturing conditions shown in Table 11. In FIG. 13, 5001 is SUS
Substrate, 5002 is an Ag thin film, 5003 is a ZnO thin film, 5
004 is a first conductivity type layer; 5005 is a first i-type layer;
006 is the second conductivity type layer, 5007 is the first conductivity type layer,
5008 is a second i-type layer, 5009 is a second conductivity type layer,
5010 is a first conductivity type layer, 5011 is a third i-type layer,
5012 is a second conductivity type layer, 5013 is ITO, 501
Reference numeral 4 denotes a current collecting electrode.

Each of the above layers was manufactured continuously to form a triple cell type photovoltaic element (element-Example 4). Table 11 shows the manufacturing conditions for each layer.

[0121]

[Table 11]

(Comparative Example 4) In this example, a-SiGe: H
The graded bandgap i-type layer is formed using a-SiGe:
H flat bandgap i-type layer and a-S sandwiching it
The triple-cell photovoltaic element shown in FIG. 15 was formed as a three-layer structure of i: H flat band gap i-type (first and second) buffer layers. Table 12 shows the manufacturing conditions for each layer. The photovoltaic element manufactured in this example is (Element-
Ratio 4).

The apparatus for manufacturing the i-type layer has a parallel plate type cathode electrode structure shown in FIG. 10 (the ratio of the cathode area to the entire grounded anode area including the conductive strip member is 0.6 times). The apparatus used in Example 4 in which the above-described three-layer film forming vacuum vessel was arranged was used.

The other points were the same as in the fourth embodiment.

[0125]

[Table 12]

Example 4 (Element-Example 4) and Comparative Example 4
The conversion efficiency, characteristic uniformity, and yield of the photovoltaic element manufactured in (element-ratio 4) were evaluated.

The current-voltage characteristics were obtained by cutting out the central part in the width direction and an area of 5 cm square from the end (5 cm from the end) every 10 m of the band-shaped member, and placed under AM-1.5 (100 mW / cm ² ) light irradiation. The photoelectric conversion efficiency was measured and evaluated. The yield was as in Example 3 (element-actual 3), Comparative Example 1 (element-ratio 3)
Cut out the photovoltaic element on the belt-shaped member prepared in the above at an area of 5 cm square at intervals of 10 m, and measure the shunt resistance in the dark state. If the resistance value is 1 × 10 ³ Ω · cm ² or more, a good product And the ratio in all the numbers was expressed as a percentage and evaluated.

Table 13 shows the above evaluation results. Table 1
Each value of Example 4 (element-actual 4) shown in FIG.
This is a numerical value normalized by setting the average value of each characteristic of (element-ratio 4) to 1.00.

[0129]

[Table 13]

From Table 13, it can be seen that each element of (element-real 4) is improved as compared with (element-ratio 4), and that the open-circuit voltage is particularly improved. It was found to be improved by a factor of 06.

As shown in Table 13, the photovoltaic element of Comparative Example 4 (element-ratio 4) was compared with Example 4 (element-real 4).
Is excellent in conversion efficiency, and it has been found that the photovoltaic element manufactured by the manufacturing method of the present invention has excellent characteristics, and the effect of the present invention has been demonstrated.

The uniformity of the characteristics in the width direction of the belt-like member was measured in Example 4.
(Element-Real 4), Photovoltaic elements on the belt-shaped member produced in Comparative Example 4 (Element-Comparative 4) were cut out every 10 m at the center and the end (5 cm from the end) in the width direction with a 5 cm square area. ,
The device was placed under AM-1.5 (100 mW / cm ² ) light irradiation, the photoelectric conversion efficiency was measured, and the width distribution of the photoelectric conversion efficiency was evaluated. Table 14 shows the variation (expressed in%) of the average value of each characteristic value at the center and the end in the width direction.

[0133]

[Table 14]

From Table 14, it can be seen that the photovoltaic element of Example 4 (Element-Comparative 4) is superior to the photovoltaic element of Comparative Example 4 (Element-Comparative 4) in the uniformity of the characteristics. The triple cell type photovoltaic element manufactured by the manufacturing method of the present invention was found to have excellent characteristics, and the effect of the present invention was demonstrated.

Further, by comparing Example 3 with Comparative Example 3, and by comparing Example 4 with Comparative Example 4, the apparatus according to the present invention can be made compact, and the weight of incidental equipment can be reduced. It was found to be effective in reducing the consumption of material gas.

[0136]

According to the present invention, a first conductive type semiconductor layer, an i-type semiconductor layer and a second conductive type semiconductor layer made of non-single crystal are formed on a continuously moving conductive strip. In the formation of a photovoltaic device having one or more sets of sequentially laminated structures, a discharge vessel provided with cut-off cathode electrodes arranged perpendicular to the moving direction of the belt-shaped member as a discharge vessel used for forming the i-type semiconductor layer The cathode potential (self-bias) at the time of discharge is set to a positive potential, and a material gas is introduced between adjacent strip-shaped electrodes and flows in a direction perpendicular to the substrate transport direction (substrate width) along the strip-shaped electrodes. By and
By changing the composition ratio (mixing ratio) of the material gas along the substrate transport direction, the film composition of the i-type semiconductor layer can be precisely controlled in the film thickness direction.

By employing the i-type semiconductor layer, a large number of photovoltaic elements having high photoelectric conversion efficiency, high quality and excellent uniformity over a large area, and having higher reproducibility and less defects can be produced in large numbers. And can be manufactured stably.

Furthermore, the size of the forming apparatus can be reduced, and the amount of material gas used can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a structure inside a discharge vessel constituting a forming apparatus of the present invention.

FIG. 2 is a schematic bird's-eye view showing an example of the cathode electrode shown in FIG.

FIG. 3 is a schematic plan view showing an example of a cathode electrode showing a position where a material gas inlet and a gas outlet are provided and a flow of the material gas.

FIG. 4 is a schematic plan view showing another example of the cathode electrode showing the positions of the material gas inlet and exhaust ports and the flow of the material gas.

FIG. 5 is a schematic plan view showing another example of the cathode electrode showing the positions of the material gas inlet and exhaust ports and the flow of the material gas.

FIG. 6 is a schematic plan view showing another example of the cathode electrode showing the positions of the material gas inlet and exhaust ports and the flow of the material gas.

FIG. 7 is a schematic plan view showing another example of the cathode electrode showing the positions of the material gas inlet and exhaust ports and the flow of the material gas.

FIG. 8 is a schematic view showing an example of a method for supplying a material gas introduced into a discharge space.

FIG. 9 is a schematic view showing another example of a method for supplying a material gas to be introduced into a discharge space.

FIG. 10 is a schematic sectional view showing an example of a conventional discharge vessel having a cathode electrode.

FIG. 11 is a schematic cross-sectional view showing an example of a photovoltaic device forming apparatus according to the present invention.

FIG. 12 is a schematic cross-sectional view of a single-cell photovoltaic device formed by the apparatus and method according to the present invention.

FIG. 13 is a schematic cross-sectional view of a triple-cell photovoltaic device formed by the apparatus and method according to the present invention.

FIG. 14 is a schematic sectional view of a conventional single-cell photovoltaic element used in Comparative Example 3.

FIG. 15 is a schematic sectional view of a conventional triple-cell photovoltaic element used in Comparative Example 4.

FIG. 16 shows S of the deposited film produced in Example 2 and Comparative Example 2.
5 is a depth profile of composition analysis by IMS.

FIG. 17 is a band profile of a deposited film produced in Example 2 and Comparative Example 2.

[Explanation of symbols]

100 vacuum vessel, 101 belt-shaped member, 103a, 103b, 103c heating heater, 104a, 104b, 104c gas introduction tube, 107 cathode electrode, 124n, 124, 124p lamp heater, 129n, 129, 129p, 130 gas gate, 131n, 131, 131p, 132 gas gate introduction pipe, 301, 302 vacuum vessel, 303, 304 bobbin, 305, 306 idling roller, 307, 308 conductance valve, 310, 311 exhaust pipe, 314, 315 pressure gauge, 513 exhaust pipe, 601, 602 vacuum Container, 603, 604 cathode electrode, 605, 606 gas introduction pipe, 607, 608 exhaust pipe, 1000 conductive strip member, 1001 vacuum vessel, 1002 cathode electrode, 1003 cut-off electrode, 1 004 ground (anode) electrode, 1005 lamp heater, 1006 exhaust port, 1007 gas inlet tube, 1008 gas gate, 1009 insulating insulator, 1010 discharge space, 1011 mass flow controller, 1012 gas cylinder, 1013 gas mixing section, 2000 conductive strip member, 2001 Vacuum container, 2002 cathode electrode, 2004 ground (anode) electrode, 2005 lamp heater, 2006 exhaust port, 2007 gas introduction pipe, 2008 gas gate 2009 insulating insulator 2010 discharge space 4001 SUS substrate, 4002 Ag thin film, 4003 Zn thin film, 4004 first 4005 i-type layer, 4006 second conductivity type layer, 4007 ITO, 4008 collector electrode, 5001 SUS substrate 5002 Ag thin film, 5003 5004 first conductivity type layer, 5005 first i-type layer, 5006 second conductivity type layer, 5007 first conductivity type layer, 5008 second i-type layer, 5009 second conductivity type layer , 5010 first conductive type layer, 5011 third i-type layer, 5012 second conductive type layer, 5013 ITO, 5014 current collecting electrode, 6001 SUS substrate, 6002 Ag thin film, 6003 ZnO thin film, 6004 first conductive type Mold layer, 6005 first buffer layer, 6006 i-type layer, 6007 second buffer layer, 6008 second conductivity type layer, 6009 ITO, 6010 current collecting electrode, 7001 SUS substrate, 7002 Ag thin film, 7003 ZnO thin film, 7004 first conductivity type layer, 7005 first buffer layer, 7006 first i-type layer, 7007 second buffer layer, 7008 7012 first conductivity type layer, 7010 first buffer layer, 7011 second i-type layer, 7012 second buffer layer, 7013 second conductivity type layer, 7014 first conductivity type 7015 Third i-type layer, 7016 Second conductivity type layer, 7017 ITO, 7018 Current collecting electrode.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Sakai 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Takahiro Yajima 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside the corporation

Claims (4)

[Claims] 1. A structure in which a first conductive type semiconductor layer, an i-type semiconductor layer, and a second conductive type semiconductor layer made of a non-single crystal are sequentially laminated on a continuously moving conductive strip. In the apparatus for forming a photovoltaic element having at least one set, the discharge vessel used for forming the i-type semiconductor layer has a surface area in a discharge space of a high-frequency power application electrode (hereinafter, referred to as a cathode electrode) provided in the discharge space. The surface area of the entire anode electrode including the surface area of the strip-shaped member is larger than the surface area in the discharge space, and the potential of the cathode electrode (hereinafter referred to as “self-bias”) when a glow discharge occurs is +30 V with respect to the grounded anode electrode including the strip-shaped member. The above positive potential can be maintained, and a part of the fin-shaped cathode electrode (hereinafter, referred to as a cut-off electrode) is transported by the belt-shaped member. A cathode structure having a plurality of electrodes vertically arranged in a direction, wherein the distance between the threshold electrodes is sufficient to maintain and maintain a discharge between the adjacent threshold electrodes; and a material used for forming the i-type semiconductor layer. A gas is introduced into the discharge space between the adjacent strip electrodes from between the adjacent strip electrodes, and flows in a direction (width direction of the strip member) perpendicular to the moving direction of the strip member along the strip electrodes.
A mechanism for applying high-frequency power to the cathode electrode to decompose the material gas by plasma discharge. 2. A gas supply means for introducing a plurality of types of material gases into the discharge space independently when introducing a plurality of types of material gases into the discharge space between the separated electrodes. An apparatus for forming a photovoltaic element according to claim 1. 3. A structure in which a first conductive type semiconductor layer, an i-type semiconductor layer, and a second conductive type semiconductor layer made of a non-single crystal are sequentially stacked on a continuously moving conductive strip. In the method for forming a photovoltaic element having at least one set, as a discharge vessel used for forming the i-type semiconductor layer, a surface area of a high-frequency power application electrode (hereinafter referred to as a cathode electrode) provided in the discharge space in a discharge space is: It has a structure that is larger than the surface area of the entire anode electrode including the surface area of the strip-shaped member in the discharge space, and the potential of the cathode electrode when a glow discharge occurs (hereinafter referred to as self-bias).
Can maintain a positive potential of +30 V or more with respect to a grounded anode electrode including the strip-shaped member, and a part of the fin-shaped cathode electrode (hereinafter referred to as a cut-off electrode) A light provided with a discharge vessel having a cathode structure, which is provided in plural in a direction perpendicular to the transport direction of the belt-shaped member, and has a gap between each of the gap-shaped electrodes, and a gap between the gap-shaped electrodes adjacent to each other, which has a sufficient gap for generating and maintaining a discharge. Using a device for forming an electromotive element, a material gas used for forming the i-type semiconductor layer is introduced into the discharge space between the adjacent strip electrodes from between the adjacent strip electrodes, and a band is formed along the cut electrode. While flowing in a direction perpendicular to the moving direction of the member (width direction of the strip-shaped member), high-frequency power is applied to the cathode electrode to decompose the material gas by plasma discharge. Forming the i-type semiconductor layer by performing the method. 4. A composition of a material gas to be introduced along a moving direction of a strip-shaped member by providing a plurality of types of material gases to be introduced into a discharge space between the boundary electrodes and guiding them independently to the discharge space. The method according to claim 3, wherein the i-type semiconductor layer is formed by changing a ratio (mixing ratio).